Define clearly the maximum time of complete interruption of blood frlow which a myocardial cell can tolerate and still survive. Determine those morphologic characteristics of the ischemic cell which correlate best with eventual cell death. This goal will include emphasis on ischemic cell swelling of both capillaries and myocardial cells. Taking into account the time course of development of these ischemic morphologic changes, define the optimal time of intervention to prevent even cell swelling by elevating extracellular osmolality. Extend the above observations obtained in a no-flow (followed by reflow) model to the low flow state. Determine the metabolic consequences of this therapeutic approach.